users: reserve service names on registration and rename

A username is also a lightning address, so a name that reads as the service
collects payments meant for it. "mint" was registered days after the ecash
redesign freed it and received payments addressed to [email protected]; the
reserved list held only "ecash", and was duplicated in two places.

One shared list now, checked on both paths, covering the service-sounding
names an account should never be able to take.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/reserved.ts b/lib/reserved.ts
new file mode 100644
index 00000000..df5f0d43
--- /dev/null
+++ b/lib/reserved.ts
@@ -0,0 +1,31 @@
+// Usernames nobody may register or rename into. A coinos username is also a
+// lightning address, so a name that reads as ours lets an account collect
+// payments meant for the service: "mint" was claimed within days of the ecash
+// redesign freeing it (2026-09-18) and took payments addressed to
+// [email protected] until it was renamed.
+//
+// Checked on registration (lib/register.ts) and on rename (routes/users.ts).
+// Names already held by the v3 registrar are refused separately, by
+// assertNameFree in lib/names.ts.
+export const reserved = [
+  "admin",
+  "administrator",
+  "ark",
+  "cash",
+  "coinos",
+  "ecash",
+  "fund",
+  "help",
+  "info",
+  "lightning",
+  "mint",
+  "pool",
+  "root",
+  "security",
+  "support",
+  "system",
+  "wallet",
+];
+
+export const isReserved = (username: string) =>
+  reserved.includes(String(username || "").toLowerCase().replace(/\s/g, ""));